we know in the time since that investigation, tamerlan traveled to russia to see his father. he spent several months there and returned to boston this past july. he's now dead, his brother is in the hospital. heather? >> all of that happening while he was applying for full citizenship. thank you, peter. >>> heather? >> thank you so much. how did the signs of these two brothers go undetected? let's asked profiler pat brown. she joins us this morning in washington. pat? >> reporter: good morning, heather. >> we can't see you. there you go. right there. tell us about this. there's certainly some red flags that popped up here, especially when the u.s. government heard from a foreign government about concerns about the older brother. so shouldn't we have done more to have looked into his backgrounds after those calls? >> i don't think so. they probably did exactly what they should have done. we have to remember, this probably wasn't the only call they've gotten from somebody that creeped somebody else out. there's a lot of psychopathic individuals running around setting off red fl